Recently, servers for three-dimensional output have been known to transmit screen data such as three-dimensional space data to a head mounted display to make this head mounted display output full dome three-dimensional space data corresponding to the user's line of sight.
In such servers for three-dimensional output, the screen data includes avatar data on avatars virtually displaying users in a virtual three-dimensional space.
In such avatar display, the constitution in which for example, the avatar is positioned based on location information on the eyeballs of a user who wears a head mounted display is disclosed (refer to Patent Document 1).